The present invention relates to a solar cell connecting apparatus, preferably a solar cell soldering apparatus, for manufacturing solar cell strings from individual solar cells and electrically conductive strips, having a first module for joining solar cells and strips together, a second module which is connected to the first module (either directly or indirectly separated by other modules, etc.), for connecting the strips to the solar cells; and a third module for transportation of the solar cells from the first module through the second module. The invention also relates to a strip retaining apparatus for a solar cell connecting apparatus such as this and to a transport apparatus for a solar cell connecting apparatus.
Solar cell soldering apparatuses are generally known and used to electrically connect individual solar cells to one another, resulting in individual solar cells being connected in series to form a so-called solar cell string. By way of example, a solar cell string such as this is specified in the document DE 201 12 309 U1.
By way of example, FIG. 1a shows a detail of a solar cell string 16. This string 16 comprises three solar cells 10, which each have a contact grid composed of individual thin electrical lines. Electrically conductive strips 12, 13 run at right angles to this contact grid and are soldered to the contact grid in order to make an electrical connection. These strips 12, 13 may extend over the entire length of a solar cell and over the length of the next adjacent solar cell, in which case the strips then pass on to the opposite face (lower face) of the solar cell, as can be seen well in FIG. 1a. In consequence, a strip pair 12, 13 connects the upper face of one solar cell 10 to the lower face of the adjacent solar cell. Furthermore, solar cells exist, as in FIG. 1b, in which one strip in each case runs transversely over the width of two adjacent solar cells and therefore connects a predecessor cell and a successor cell to one another, with appropriate polarity.
In FIG. 1c, strips likewise extend, interleaved in one another, in the longitudinal direction of adjacent cells. The strips (by way of example 5 of them) connect the rear face to the rear face of adjacent cells. Since, in FIGS. 1b and 1c, the strips are located only on the rear face of the solar cells, the expression rear-face contact cells is used in these cases.
Connections of this type are then repeated for the entire row of solar cells thus finally resulting in a solar cell string which is formed from a multiplicity of individual solar cells, with the individual solar cells being electrically connected via the strips 12, 13. The expression “strips” is used in the following text to represent an electrically conductive connector whose shape may extend from a pure strip shape (for example, FIG. 1, 1c) to geometries matched to the contours (for example, FIG. 1b).
Solar cell soldering apparatuses have been proposed, for example, those in DE 102 97 633 T5, in order to produce a solar cell string 16 such as this. In the solar cell arrangement machine disclosed there, the solar cells to be connected are located on a plate which is passed through the machine with the aid of stepping motors. Gripping elements are provided on this plate, grip the individual solar cells, and fix their positions with respect to one another. The strips which are required to connect the individual solar cells are placed down, are likewise firmly clamped to the solar cell and are then moved through a soldering station.
The use of a plate for transportation of the solar cell string is disadvantageous, inter alia with regard to a high cycle rate. Furthermore, it has little flexibility in terms of different solar cell sizes, distances between the solar cells in the string (gap size) and a different number of solar cells in a solar cell string. There are disadvantages, likewise, in the various zones of the connecting process (for example, preheating, soldering, cooling-down zones), which require specific process parameters because of the high quality of the connection process and may extend over relatively long path lengths. Furthermore, the number of solar cells to be connected is dependent on the length of the horizontally moving plate. When the plate is moved back, this results in a movement with no load, with a negative effect on the yield.